Childhood epilepsy syndromes

• Childhood epilepsy syndromes are recognisable combinations of seizure type, age of onset, EEG pattern, imaging and development; naming the syndrome matters because it changes treatment and prognosis.
• The ILAE divides childhood syndromes into three groups: self-limited focal epilepsies, generalised epilepsies, and developmental or epileptic encephalopathies. ^[4]
• Infantile spasms present in the first year with clusters of flexor or extensor jerks, hypsarrhythmia on EEG and developmental delay or regression; they need urgent specialist treatment. ^[5]
• Childhood absence epilepsy causes brief staring spells with three per second spike-and-wave on EEG and is usually outgrown; its first-line drug is ethosuximide.
• Self-limited epilepsy with centrotemporal spikes is the commonest self-limited childhood focal epilepsy: it usually begins in mid-childhood and is outgrown by adolescence. ^[6]
• Lennox-Gastaut syndrome is a severe childhood encephalopathy with tonic and other seizures and slow spike-and-wave on EEG; it is treated stepwise under a paediatric neurologist.

By the end of this page you should be able to:

1. Place the main childhood epilepsy syndromes in the ILAE groups and say what makes each syndrome a syndrome (mandatory seizure and EEG features).
2. Recognise infantile spasms, childhood absence, self-limited epilepsy with centrotemporal spikes and Lennox-Gastaut syndrome from their age, seizure semiology, EEG and development.
3. Explain how to investigate a child with a suspected first unprovoked seizure, including when EEG, MRI and genetic testing are indicated.
4. Apply the NICE NG217 treatment ladder for absence, self-limited epilepsy with centrotemporal spikes, infantile spasms and Lennox-Gastaut syndrome, and say which drugs can worsen a syndrome.
5. Cross-check a prolonged or complicated febrile seizure against the higher risk of later epilepsy and say when to refer.
6. Plan follow-up, safety, family support and low-resource care for a child with one of these syndromes.

A syndrome is not always identifiable at the first seizure. The 2017 ILAE classification described by Specchio and colleagues lists fifteen childhood-onset syndromes in three groups: (1) self-limited focal epilepsies (self-limited epilepsy with centrotemporal spikes, self-limited epilepsy with autonomic seizures, childhood occipital visual epilepsy, photosensitive occipital lobe epilepsy); (2) generalised epilepsies (childhood absence epilepsy, epilepsy with myoclonic absence, epilepsy with eyelid myoclonia); and (3) developmental or epileptic encephalopathies (epilepsy with myoclonic-atonic seizures, Lennox-Gastaut syndrome, developmental or epileptic encephalopathy with spike-and-wave activation in sleep, hemiconvulsion-hemiplegia-epilepsy syndrome, febrile infection-related epilepsy syndrome) ^[4]. This page works through the four syndromes most often met in practice and cross-checks them against febrile seizures. ^[6]

An epileptic seizure itself is an abnormal, hypersynchronous discharge of cortical neurones causing transient signs and symptoms. Epilepsy is a brain disorder with an enduring predisposition to generate seizures, with cognitive, psychological and social consequences. A syndrome diagnosis is made when the seizure type, EEG and clinical picture match a pattern rather than on one feature alone.

Most epilepsy begins in childhood. Within childhood epilepsy, self-limited syndromes are common and have a good outcome, while developmental and epileptic encephalopathies are rarer and more serious. The four syndromes on this page sit at different points along that spectrum:

• Self-limited epilepsy with centrotemporal spikes is the commonest self-limited childhood focal epilepsy syndrome ^[6].
• Childhood absence epilepsy is one of the commonest generalised epilepsies of school age.
• Infantile spasms mainly affects children in their first year of life ^[5].
• Lennox-Gastaut syndrome is one of the more common developmental and epileptic encephalopathies of early childhood.

Exact regional incidence figures vary between series and are not reproduced here, because prevalence studies use different case definitions. Regionally, genetic, structural and infectious causes of epilepsy are not evenly distributed: in many low- and middle-income settings infections, including neonatal infection and cysticercosis, and birth injury make structural epilepsy commoner than in high-income settings, so a child presenting with a suspected syndrome needs the underlying cause to be sought.

Childhood syndromes arise from the interaction of brain development, genes and sometimes a preceding insult. Grouping causes helps investigation:

• Genetic or presumed genetic syndromes. Childhood absence epilepsy, self-limited epilepsy with centrotemporal spikes and epilepsy with myoclonic-atonic seizures are classified as genetic or idiopathic generalised or focal syndromes, with no structural lesion on imaging. Mutations in ion-channel genes are implicated in many of them.
• Structural or metabolic causes. Infantile spasms and Lennox-Gastaut syndrome are common after perinatal injury, hypoxic-ischaemic encephalopathy, cortical malformation, tuberous sclerosis complex, metabolic disease and central nervous system infection. Tuberous sclerosis complex is a special case: spasms due to tuberous sclerosis are treated differently.
• Unknown cause. A proportion of children never get a single named cause; in these cases genetic testing becomes more important.
• Fever and infection. Febrile seizures usually do not become epilepsy, but complicated febrile seizures can be associated with later epilepsy, especially when predisposing factors are present ^[1]. This is the cross-check discussed later in this page.

Risk factors for a first seizure becoming epilepsy include a neurological abnormality, an abnormal EEG after the first seizure, a structural brain lesion, and a complicated febrile seizure with features such as focal onset or duration longer than ten minutes ^[1]. An abnormal neonatal history raises the chance of a structural cause in a baby with spasms.

Seizures are generated by an imbalance between excitation and inhibition in cortical networks. Each syndrome has a characteristic mechanism that explains its semiology and EEG:

• Infantile spasms. These are a type of epileptic spasm occurring mainly in infants. They are thought to reflect widespread cortical and subcortical network dysfunction at a sensitive stage of brain development. The EEG shows hypsarrhythmia: high-voltage, chaotic, multifocal slow waves with spikes. The clinical correlate is developmental delay or regression, because the abnormal activity disrupts development rather than just interrupting it ^[5].
• Typical absence. In childhood absence epilepsy, abnormal thalamocortical rhythms generate bilaterally synchronous spike-and-wave discharges. The child stops, stares and does not respond for a few seconds, then resumes as if nothing happened, because the entire network resets.
• Atypical absence and Lennox-Gastaut. These are associated with slower, irregular spike-and-wave at less than three per second and with tonic and other seizure types; the underlying problem is more severe, often structural, and development is affected.
• Centrotemporal spikes. In self-limited epilepsy with centrotemporal spikes, the Rolandic cortex around the central sulcus generates spikes that spread in sleep, producing unilateral facial or oropharyngeal motor seizures. The activity is sleep-activated, which is why a sleep EEG is so often the first diagnostic test. The syndrome is self-limited because the underlying network changes with brain maturation.
• Febrile and reflex triggers. Fever lowers the seizure threshold in a susceptible child. Febrile seizures are usually a threshold phenomenon, not a syndrome of epilepsy, and most children never develop unprovoked seizures.

• Age. The disorder mainly affects infants in their first year of life ^[5].
• Seizure. Brief, clustered events: flexion of the head, trunk and limbs (or extension, or mixed), often on waking, sometimes mistaken for colic, startle or reflux. Parents may describe "a jack-knife" movement repeated many times in a few minutes.
• Development. Developmental delay or regression is a defining feature, not an incidental one ^[5].
• EEG. Hypsarrhythmia: high-voltage chaotic slow activity with multifocal spikes. A sleep EEG is more sensitive.
• Other clues. Spasms can be preceded or accompanied by other seizure types in a severe encephalopathy. Ask about skin (hypopigmented macules, shagreen patch) for tuberous sclerosis, and about perinatal history.

• Age. School-age onset, peaking in mid-childhood.
• Seizure. Sudden brief lapse of awareness (blank stare, pause in activity) lasting a few seconds, with abrupt onset and offset, often tens to hundreds per day. The child is not aware of them. Hyperventilation can trigger one, which is useful for diagnosis.
• Development. Usually normal intellect and development, although subtle attention problems occur.
• EEG. Generalised spike-and-wave, activated by hyperventilation.
• Atypical absence. Longer, less abrupt onset and offset, with more tonic features and slow spike-and-wave at less than 3 per second. Atypical absence suggests a more severe syndrome such as Lennox-Gastaut rather than childhood absence epilepsy ^[7].

• Age. Onset in mid-childhood; the syndrome is self-limited and most children outgrow it by adolescence ^[6].
• Seizure. Seizures occur mainly around sleep. Typical semiology is hemifacial clonic twitching, dysarthria or drooling with preserved awareness; speech arrest and unilateral tonic posturing of the mouth or face are common. They may generalise. Emotional or sensorimotor auras are not expected.
• Development. Normal development between seizures, although school performance can suffer if seizures or EEG spikes are frequent.
• EEG. Centrotemporal (Rolandic) spikes with a characteristic morphology, often bilateral and markedly activated in non-REM sleep.
• Imaging. Normal; MRI is not needed for the typical case.

• Age. Onset in early childhood.
• Seizure types. Multiple, prominently tonic seizures, atonic or "drop attacks", atypical absence and generalised tonic-clonic seizures. The combination, not one seizure type, defines it.
• Development. Developmental impairment or regression is an expected part of the syndrome.
• EEG. Slow spike-and-wave and bursts of paroxysmal fast activity in sleep (generalised fast rhythms). The slow spike-and-wave differs from the fast discharge of tonic seizures.
• Associations. A history of infantile spasms, West syndrome, severe perinatal injury, malformation of cortical development or tuberous sclerosis complex is common.

The two questions are whether the event is an epileptic seizure at all, and which syndrome it represents. A table of the main mimics:

Within the syndromes, the most common confusions are:

• Infantile spasms versus colic, reflux, startle or dystonia: spasms are clustered, stereotyped and tied to hypsarrhythmia.
• Childhood absence versus daydreaming: hyperventilation during EEG precipitates absence in the clinic.
• Self-limited epilepsy with centrotemporal spikes versus migraine aura or psychogenic focal seizure: the sleep-activated centrotemporal spikes settle the diagnosis.
• Lennox-Gastaut versus multifocal epileptic encephalopathy: the tonic seizures and slow spike-and-wave pattern point to the syndrome.

NICE NG217 structures the assessment, and the following points are taken from its diagnosis chapter ^[1].

1. History and examination. Detailed eyewitness and video account; full examination including skin and neurocutaneous signs.
2. Electrocardiogram. Offer a 12-lead ECG after a first suspected seizure, to exclude a cardiac mimic.
3. Metabolic screen. Exclude hypoglycaemia and other metabolic disturbance.
4. Electroencephalogram. Consider routine awake EEG with provoking manoeuvres (hyperventilation, photic stimulation) to support diagnosis and classify the syndrome; perform as soon as possible, ideally within 72 hours of the seizure if one is requested after a first seizure. Do not use EEG to exclude epilepsy. Add a sleep-deprived EEG, ambulatory EEG or sleep EEG if uncertainty remains; sleep EEG is essential for infantile spasms and for self-limited epilepsy with centrotemporal spikes. ^[1]
5. Neuroimaging. Offer MRI to children diagnosed with epilepsy unless they have idiopathic generalised epilepsy or self-limited epilepsy with centrotemporal spikes; the MRI should be carried out within six weeks of the request, using a regionally agreed epilepsy protocol. If MRI is contraindicated, consider CT. ^[1]
6. Genetic testing. Discuss with a neurologist or geneticist. Consider whole-genome sequencing for epilepsy of unknown cause with onset under 2 years, for clinical features suggesting a specific syndrome (such as Dravet syndrome), or with additional learning disability, autism spectrum disorder, structural abnormality or cognitive decline. For onset between 2 and 3 years, whole-genome sequencing may be considered if a specialist multidisciplinary team agrees. ^[1]
7. Antibody testing. Consider it when autoimmune encephalitis is suspected, in discussion with a neurologist.
8. Referral. Refer urgently for an appointment within 2 weeks after a first suspected seizure; for children and young people, to a paediatrician with expertise in first seizures. Infantile spasms under 2 years: seek guidance from and refer urgently within 24 hours to a tertiary paediatric neurologist. ^[1]

Childhood epilepsy syndromes are electroclinical and do not rest on a single test. The essential components are:

• Infantile spasms syndrome. Clustered epileptic spasms, usually in the first year; hypsarrhythmia or modified hypsarrhythmia on sleep EEG; and developmental delay or regression. Urgent assessment under 2 years (see the NICE recommendation above).
• Childhood absence epilepsy. Typical absence seizures with abrupt onset and offset, lasting a few seconds and usually under ten seconds ^[7], with three per second generalised spike-and-wave on EEG; onset in childhood; normal or near-normal development.
• Self-limited epilepsy with centrotemporal spikes. Focal seizures with a centrotemporal (Rolandic) semiology, normal development and typical centrotemporal spikes on EEG; imaging normal ^[6].
• Lennox-Gastaut syndrome. Multiple seizure types including tonic and atonic, developmental impairment and slow spike-and-wave or generalised paroxysmal fast activity on EEG.
• Epilepsy with myoclonic-atonic seizures. Generalised myoclonic-atonic seizures in childhood with EEG features and, usually, developmental impact. This syndrome sits alongside Lennox-Gastaut in the encephalopathy group.

A syndrome may not be evident at the first or second seizure. Reassess as the EEG, imaging and developmental picture evolves.

NICE guideline NG217 (published 2022, last updated August 2026) gives a treatment ladder for each syndrome. These recommendations are evidence-based; many drugs are used off label in children, and several carry safety warnings. The overall sequence for the common childhood syndromes is summarised below, then handled syndrome by syndrome.

Febrile seizures are not epilepsy, and the management of the fever differs from the management of a syndrome. The clinically useful cross-check for this topic is the risk that a febrile seizure heralds epilepsy:

• A simple febrile seizure in an otherwise normal child is usually benign, with a low risk of epilepsy.
• Children with complicated febrile seizures lasting longer than ten minutes or with focal or prolonged features have a higher risk of epilepsy, especially if other predisposing factors are present ^[1].
• Children presenting with a first afebrile seizure are at increased risk of further afebrile seizures, especially within 6 to 12 months, compared with children with febrile seizures ^[1].
• The decision to do urgent neuroimaging, lumbar puncture or treatment in a febrile seizure rests on the fever syndrome and the child's age, not on the NICE childhood epilepsy ladders on this page.

If a child has epilepsy plus febrile seizures, treat the syndrome and manage fever and fever-duration risk separately.

• Safety. Sodium valproate should not be started for the first time in people under 55 years unless two specialists independently agree and document that there is no other effective or tolerated treatment, or there are compelling reasons that the reproductive risks do not apply. Valproate must not be used in women and girls of childbearing potential unless other options are unsuitable and a pregnancy prevention programme is in place. Topiramate should not be used in women of childbearing potential unless the conditions of a pregnancy prevention programme are fulfilled. These MHRA warnings apply even though valproate is NICE's recommended first-line drug for severe syndromes such as Lennox-Gastaut. ^[8]
• First-line versus monotherapy language. NICE generally uses "consider" rather than "offer" for syndromes, reflecting the difficulty of enrolment and the need for specialist choice. The "offer" wording for absence seizures and generalised tonic-clonic seizures is stronger.
• Off-label. Many antiseizure medicines are used off label in children; this does not make their use inappropriate, but the rationale must be documented in tertiary care.
• Monitoring. For infantile spasms, review weekly during the first weeks of treatment, repeat sleep EEG at 2 weeks after starting treatment and then monthly; for childhood absence, routine clinical review and EEG help, because seizures are often invisible to parents.
• Exacerbation lists. The drugs that can worsen absence and myoclonic seizures (carbamazepine, gabapentin, lamotrigine for myoclonic, oxcarbazepine, phenytoin, pregabalin, tiagabine, vigabatrin) and the longer list for generalised tonic-clonic and focal seizures must be checked before prescribing for any syndromic child ^[2].
• Non-pharmacological options. Ketogenic diet under a ketogenic diet team is a recommended add-on in infantile spasms, Lennox-Gastaut, myoclonic-atonic epilepsy and treatment-resistant focal epilepsy. Surgery and neuromodulation belong to tertiary epilepsy services.

• Status epilepticus and prolonged seizures. Any child with a prolonged seizure needs emergency treatment along NICE NG217 (benzodiazepine first-line) and hospital review.
• Injury. Tonic and atonic seizures in Lennox-Gastaut syndrome carry a high risk of falls and head injury; protective helmets, safe seating and floor care help.
• Cognition and behaviour. Developmental delay in encephalopathic syndromes, and subtle attention or language deficits in absence and self-limited epilepsy, affect schooling.
• Psychiatric comorbidity. Anxiety, attention problems and depression are increased; NICE recommends routine assessment of neurobehavioural comorbidity in epilepsy.
• Medication harm. Sedation, behavioural change on levetiracetam, vigabatrin-associated visual field constriction (informed consent and periodic visual fields), steroid side effects, and valproate teratogenicity.
• Sudden unexpected death in epilepsy (SUDEP). Risk is higher with uncontrolled or generalised tonic-clonic seizures; address seizure control, nocturnal safety and SUDEP discussion sensitively with families.

• Infantile spasms. Seizures can be stopped, but long-term development depends heavily on cause and on how quickly spasms were controlled. The phrase "cure versus control" must be used honestly: spasm freedom is achievable in many, normal development less often.
• Childhood absence epilepsy. Most children outgrow absence during adolescence, but some develop other seizure types; a subset continues into adult life. Early ethosuximide control is favourable.
• Self-limited epilepsy with centrotemporal spikes. The large majority outgrow it by adolescence and are medication-free; adult epilepsy is uncommon.
• Lennox-Gastaut syndrome. A lifelong epilepsy for many, with persistent seizures and cognitive disability in most; treatment goals shift to reducing tonic and drop attacks and protecting development where possible.
• Febrile seizures. Usually benign; recurrence risk and later epilepsy risk depend on age at onset and number of risk factors.

• Girls and women of childbearing potential. Valproate and topiramate warnings must be addressed years before adulthood, because valproate is teratogenic and both drugs fall under pregnancy prevention programmes. Alternative strategies should be sought in Lennox-Gastaut and absence when possible.
• Pregnancy. Many childhood syndromes remain active into adulthood. Pre-conception counselling, folate and specialist review reduce risk; avoid valproate unless two specialists agree it is the only effective option.
• Boys and men. Valproate advice includes effective contraception throughout treatment and for three months afterwards, plus discussion of possible fertility risks for those planning a family within a year.
• Children with tuberous sclerosis. Vigabatrin is first line for spasms; cannabidiol may be used for tuberous sclerosis-related seizures in some children aged 2 years and over.
• Neonates and infants under 2 years. Whole-genome sequencing is considered for epilepsy of unknown cause with onset at this age; spasm work-up must be fast.
• Children with learning disability or autism. Syndromes may be harder to recognise; behavioural change rather than seizure frequency may dominate. Reasonable adjustments and epilepsy specialist nursing support help.

• A clinical history and a 12-lead ECG and blood glucose can be done almost anywhere; a sleep EEG can be arranged regionally and is essential before diagnosing a syndrome.
• Where MRI is delayed, the syndrome can still be recognised clinically and treatment started; reinvestigate if the diagnosis is doubtful or seizures are drug-resistant.
• Steroids and vigabatrin for spasms, ethosuximide and sodium valproate for absence and generalised syndromes, and lamotrigine are available in many settings. Doses should be titrated per local formularies and the NICE and BNF for children; monitor renal, hepatic and safety limits.
• Ketogenic diet can be delivered with local foods, but it needs a team and family education.
• Children injured during drop attacks need practical prevention: helmets, cushioned environments and safe sleep positions; these are low cost and high yield.
• Genetic testing, advanced imaging and neuromodulation may not be available; build care around referral to tertiary centres.

• Febrile seizures
• Neonatal seizures and hypoxic-ischaemic encephalopathy
• Autism, ADHD and developmental delay
• Dehydration and paediatric fluids (for status epilepticus resuscitation)
• Hydrocephalus and neural tube defects
• Poisoning and ingestions in children